Methods for inkjet printing objects for microfluidic devices
Provided herein are methods for inkjet printing objects, including objects which may be used as elements of microfluidic devices. The microfluidic devices incorporating the elements are also provided. Such microfluidic devices include those configured to quantify the expression and activity of exosomal matrix metalloprotease, MMP14. These microfluidic devices may be used in methods of monitoring breast cancer in patients having breast cancer.
1 . A method for inkjet printing an object, the method comprising:
(a) depositing a first droplet of an ink composition comprising particles dispersed in a liquid phase onto a surface of a substrate at first location and evaporating the liquid phase from the deposited first droplet to form a first ring structure on the surface at the first location, the first ring structure comprising the particles;
(b) depositing a second droplet of the ink composition onto the surface at a second location laterally offset from the first location by a droplet spacing value and evaporating the liquid phase from the deposited second droplet to form a second ring structure on the surface at the second location, the second ring structure comprising the particles, wherein the second ring structure is offset from, and partially overlap s with, the first ring structure; and
(c) repeating step (b) one or more additional times with one or more additional droplets to form a first layer of offset and partially overlapping ring structures on the surface of the substrate, the first layer comprising the first and second ring structures and one or more additional ring structures formed from the one or more additional droplets, thereby forming an object.
2 . The method of claim 1 , further comprising repeating steps (a), (b), and (c) one or more additional times to form one or more additional layers of offset and partially overlapping ring structures on the first layer.
3 . The method of claim 2 , further comprising forming an array of objects distributed across the surface of the substrate, each object in the array formed by carrying out steps (a), (b), and (c) and repeating steps (a), (b), and (c) one or more additional times.
4 . The method of claim 1 , wherein the droplet spacing value is in a range of from 2 μm to 10 μm.
5 . The method of claim 1 , wherein the ink composition is a colloidal suspension.
6 . The method of claim 1 , wherein the particles comprise silica particles, carbon particles, polystyrene particles, and combinations thereof.
7 . The method of claim 1 , wherein the particles are spherical.
8 . The method of claim 7 , wherein the particles have an average diameter in a range of from 100 nm to 5 μm.
9 . The method of claim 1 , wherein the substrate is an unmodified substrate.
10 . The method of claim 1 , wherein the ink composition is free of a surface tension modifier.
11 . The method of claim 1 , further comprising functionalizing the formed object so that the object is capable of capturing a target species.
12 . The method of claim 11 , wherein the object is functionalized with an antibody specific to an exosome.
13 . The method of claim 12 , wherein the antibody is anti-CD81 monoclonal antibody.
14 . The method of claim 1 , wherein each of the first ring structure, the second ring structure, and the additional ring structures have a circular shape and define an aperture through which at least some of the surface of the substrate is exposed.